How to Design the Correct Intelligent Configuration of an LED Display Screen

introduction

In recent years, with the rapid development of LED industry, there are many display models and specifications, and a hundred flowers bloom, which not only gives users more choices, but also makes the display effect of LED display more colorful. However, too many models and specifications bring some problems in engineering application. Due to many manufacturers and no unified standards, the installation and commissioning of LED display screen has become a very heavy work. In addition, the installation and commissioning involves more than 20 parameters, and the requirements are very high. Generally, only professional technicians can complete it. In fact, most of the installation and commissioning are repetitive work, which makes many professional and technical personnel fall into the on-site commissioning of various projects, resulting in a great waste of manpower. Therefore, some people put forward that it is possible to debug and form data files ahead of time, professional technicians do not need to go to the scene, and the general engineers can finish debugging at the scene downloading, so LED intelligent configuration technology arises at the historic moment. After market research, some LED control software has also realized the function of intelligent configuration, but the effect is not ideal, such as too many steps, non intuitive, complex and so on. Based on this, after research, this paper proposes an intelligent configuration method, which allows users to make choices only through the "next step", automatically complete the intelligent configuration in at least seven steps, debug successfully, and generate data files for storage and download.

1. Main functional requirements analysis and model constructionDue to different manufacturers, the number of parameter items of their display screen is also different, but basically each display screen has more than 20 items. After analysis and classification, it can be divided into core parameters, basic parameters and auxiliary parameters.(1) Core parameters

The core parameters are necessary for the display screen. If the setting is incorrect, it will not be displayed if it is light, and it will burn the screen if it is heavy. The core parameters include 8 items: cascade direction, OE polarity, data polarity, display type, color, scanning mode, point sequence and line sequence.(2) Basic parametersBasic parameters are the basic parameters of the display screen. If they are not set correctly, they cannot communicate, do not display or display abnormally. The basic parameters include 12 items: display width, display height, control card address, baud rate, IP address, port number, MAC address, subnet mask, gateway, display refresh frequency, shift clock frequency and line blanking time.

(3) Auxiliary parametersAuxiliary parameters are parameters set for better display and control, including control card name, communication display mark, brightness and on-off screen time.

To sum up, a display screen needs to be correctly configured with more than 20 parameters to light up, which is cumbersome and complex. If the setting is incorrect, it will not be displayed at first, or it will burn down the display screen, resulting in significant economic losses and construction delay. This is because the price of general display screen is more than 1000 yuan, some even more than one million yuan. Therefore, for the sake of prudence and prudence, it is understandable that some LED control software has complex design and inconvenient use. In order to overcome the shortcomings of the existing software, reduce the use threshold and complete the hardware debugging of the display screen in a relaxed and natural process, after research, this paper constructs a complete display screen parameter configuration model and intelligent configuration model, as shown in Figure 1 and Figure 2.

In Figure 1, for the configuration of basic parameters and auxiliary parameters, input boxes and selection boxes are provided. After user input and selection, it can be set directly by connecting the display screen. For the core parameters, three methods can be used: professional quick query, intelligent configuration and external file configuration.(1) Professional quick checkThe parameters of common and commonly used display screens are generally fixed. At this time, they can be sorted into files or tables in advance, and the configuration can be loaded during debugging.

(2) Intelligent configurationFor the uncommon or uncertain display screen, its parameters are unknown. At this time, intelligent configuration can be adopted to determine its configuration parameters, and then save them for future use.(3) External file configuration

Import an external file built by intelligent configuration or other methods into the configuration.Among the three configuration methods of core parameters, intelligent configuration is the focus of this paper. Its main processes and functions are as follows:(1) Start intelligent configuration;

(2) Through the wizard, let the user and the display screen make human-computer interaction selection, start the intelligent configuration operation, and complete the determination of core parameters by filling in initial parameters, determining OE polarity / data polarity, determining color, determining scanning mode, determining point sequence, determining line sequence, generating configuration parameters, etc;(3) Return intelligent configuration parameters;(4) Connect the display screen and set parameters;

(5) If it is correct, perform the output parameter operation;(6) Select an external file and save it for later download. At this point, the intelligent configuration of the display screen is completed.2. Design and implementation of key functions

2.1 fill in initial parameters

The whole intelligent setting process is operated for the display module. For the display screen, it is exactly to observe the first display module entering from the signal cascade direction. That is, if the signal cascade direction is from left to right, the first display module refers to the display module in the upper left corner of the display screen. If the signal cascade direction is from right to left, the first display module refers to the display module in the upper right corner of the display screen. In order to facilitate observation, only one display module is used for general intelligent setting, and confirm that the display module is good and fault-free (including lines or points without abnormal display).

After selecting the display module, fill in the parameters such as signal cascade direction, number of module width points, number of module height points and display type, and then click next to start intelligent configuration.2.2 determining OE polarity and data polarity

OE polarity and data polarity are extremely important parameters of the display screen, in which OE polarity determines whether the display screen is on, and data polarity determines whether the display is correct. If the OE polarity is incorrect, the display will not be lit, no matter what the data polarity is; If the data polarity is incorrect, the display is abnormal and is all on. Therefore, the primary task of intelligent configuration is to judge OE polarity and data polarity. The display module displays three options: "full bright", "full black / dark bright" and "other displays or irregular changes". If "other displays or irregular changes" is selected, it indicates that there is a problem with the hardware configuration. The intelligent configuration needs to be carried out after the hardware configuration is corrected. In the specific design, 0 represents the high level and 1 represents the low level. The values of OE polarity and data polarity are determined by sending the high and low levels in turn and the user selects on or off. In this way, there are four combinations of OE polarity and data polarity. Therefore, it takes only four steps to correctly judge the OE polarity and data polarity. As long as the corresponding values of OE polarity and data polarity are sent in turn, and then the user's selection at each step is recorded, the values of OE polarity and data polarity can be judged.

2.3 color determination

Gray free display screen is divided into monochrome, two-color and full-color, of which monochrome generally corresponds to red; Two colors are generally red and green; Full color is generally red, green and blue. For monochrome screen, this step can be omitted; For the two-color screen, send the red command. According to the displayed color, you can judge whether it is normal display or red and green reverse color; For the full-color screen, send red and green colors respectively. According to the displayed color, you can judge whether it is normal display or red green reverse color, red blue reverse color or green blue reverse color.

2.4 determine scanning modeFor the scanning mode, the judgment formula is: module height / number of lit lines = scanning mode. In design, send the command to judge the scanning mode. According to the number of lines selected by the user, the scanning mode can be calculated by formula. Since the scanning mode is uncertain, the data output shall be carried out according to the high denominator scanning mode determined in the early stage, and the number of bright lines is capped as the module height parameter.2.5 determining the order of points

In fact, the LED display screen is displayed in the order of one point by one point, but it uses the delay characteristics of human vision to realize the effect of full screen image display update by quickly sending the images of all points on the full screen at one time. Therefore, the order of points must be determined before sending.In order to obtain the point sequence, you can send a point at an interval of one second, and then record its position. The specific implementation method is as follows:(1) Send dot command; (2) One LED pixel on the display module will be lit every second. Carefully observe the lighting sequence of these pixel points. After confirming the lighting sequence, you can click the grid on the corresponding position of the simulation display module diagram (each grid of the simulation diagram corresponds to a pixel of the display module) according to the lighting sequence; (3) Click "next" after dotting, and the system will automatically record the dotting sequence.

In order to better help users determine the order of points, the system also provides functions such as re management, fallback, reset and deduction.2.6 determining line orderIn addition to the order of highlights, determine the line order of highlights. In order to obtain the row order, you can send a row every second, send a point for each row, and then record its position. The specific implementation method is as follows: after sending the line display command, observe the lighting sequence of the LED lights on the display driving board, and trace the corresponding sequence points at the relative position of the line sequence. When finished, click next to record the line sequence automatically.

For the display screen with common specifications, the line sequence can be determined through the section "2.5 determining the point sequence". This step can be omitted. At the same time, in order to better help the user determine the line sequence, the system also provides the functions of re entering the line sequence, fallback, reset and so on.2.7 download parameters and complete intelligent configurationAfter the above parameters are determined, reorganize the sequence and format according to the display data configuration format, and then download to the display configuration, and then observe whether it is correct. If it is correct, the intelligent configuration is completed. In addition, if necessary, it can be saved to a file for later use; If it is not correct, analyze the reason, and then conduct intelligent configuration again.

3. Conclusion